This application requests five additional years of support for training in population research at the Center for Demography and Ecology, University of Wisconsin-Madison. Although we have expanded our interdisciplinary activities and the breadth of our training, we are requesting the same number of predoctoral (8) and postdoctoral (1) stipends. The Center for Demography and Ecology has for more than 40 years offered a world-class program of training in population science. Its graduates are among the most renowned demographers and population scientists. The training program is based on three critical ingredients: outstanding faculty conducting solid research on critical problems;high quality resources for faculty and student research and study;and a well-designed and fully implemented curriculum combining course work and research experience. During the past 5-10 years, CDE responded to anticipated increases in retirement rates by helping affiliated departments aggressively recruit top young population scientists. New and stronger ties across departments and disciplines enhance students'interdisciplinary training experiences. The international components of CDE's research portfolio have grown explosively in the past five years, producing an extensive and exceedingly rich set of international projects and networks through which students can develop their own international research agenda. The 51 members of the CDE training faculty offer a rich curriculum and extraordinary opportunities for students to participate on a wide variety of research projects. Research resources provided to students from CDE's infrastructure grant, individual grants and university support are outstanding. Together with a demanding curriculum and an intensive apprenticeship system, CDE's human and material resources produce the best possible environment for pre and postdoctoral training in population research.